<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>chatAt</title>
</head>
<body>
	<script type="text/javascript">
		var str="Hello World";
		console.log(str.charAt(0));//去除字符串索引为0的字符
		console.log(str.charCodeAt(5));//获取索引为5的字符编码 
		//从一个字符串中找到给定的字符串，返回出现的位置,没找到返回-1
		var email="1067998193@qq.com";
		console.log(email.indexOf("@"));
	</script>
</body>
</html>